An aircraft heat exchanger is sometimes exposed to icing conditions at its cold inlet face. Cold air flow from the turbine of an air cycle machine or sub-freezing ambient air may contain snow or ice particles that can damage the leading edges of the cold inlet fins. Flow blockages are caused when the leading edges are bent, or when the snow and ice particles accumulate on the cold inlet face at a rate that exceeds its melting capability. Snow or ice particles can also pierce hot fluid passages and cause leaks that reduce system efficiency.
One method of providing ice protection is to make the cold air flow bypass the heat exchanger when snow or ice accumulates on the cold inlet face until the face has warmed sufficiently to melt the accumulation. This, however, requires additional parts at the cold inlet face which can be difficult to fit into the available space on an aircraft. Accordingly, there is a need for a cold inlet face design with integral ice-melting features.